The invention relates to a 12-speed transmission for utility vehicles in 2.times.3.times.2 construction.
Such 12-speed transmissions consist of a front-mounted or split section, a 3-gear main section and a rear-mounted or range section wherein each section has pneumatically or manually actuated shifting devices. The front-mounted and rear-mounted sections are usually pneumatically actuated while the main section is manually shifted. For the manual shift, shifting devices are used which are based on those of 16-speed transmissions. However, the shift diagram that results has a blank, i.e. the shift diagram does not allow any uninterrupted complete shifting of the gears with movements alternating in direction. From the third to the fourth gear, the selector lever, after disengaging the third gear, has to be shifted in the same direction again as in the engagement of the third gear. Thereafter the fifth gear is switched by a direct opposite movement. As a result of this, a shift blank is formed between the second and fifth gear. Such a shift diagram is illogical as to the movement sequence and makes the control of the shifting device difficult or, at least, is unusual.
The problem to be solved by the invention is to modify a 12-speed transmission in 2.times.3.times.2 construction so as to obtain a conventional logical shift diagram without shift blanks.